TWI858004B - Adhesive composition, film-shaped adhesive, adhesive sheet, and method for manufacturing semiconductor device - Google Patents

Abstract

The present invention discloses an adhesive composition, comprising a thermosetting resin, a hardener and an elastomer, wherein the thermosetting resin comprises an epoxy resin having a lipid epoxide, and the elastomer comprises an elastomer having a carboxyl group. In addition, a film-shaped adhesive using the adhesive composition is disclosed. Furthermore, a method for manufacturing an adhesive sheet and a semiconductor device using the film-shaped adhesive is disclosed.

Description

Adhesive composition, film-shaped adhesive, adhesive sheet, and method for manufacturing semiconductor device

The present invention relates to a method for manufacturing an adhesive composition, a film-like adhesive, an adhesive sheet, and a semiconductor device.

Previously, silver paste was mainly used to bond semiconductor chips to supporting components for carrying semiconductor chips. However, with the miniaturization and integration of semiconductor chips in recent years, the supporting components used have also begun to be required to be miniaturized and fine-grained. On the other hand, when silver paste is used, problems such as defects during wire bonding, difficulty in controlling film thickness, and the generation of voids may occur due to paste exposure or the slope of the semiconductor chip.

Therefore, in recent years, a film adhesive for bonding semiconductor chips and supporting members has been used (for example, refer to Patent Document 1). When using a bonding sheet including a dicing tape and a film adhesive laminated on the dicing tape, a semiconductor chip with a film adhesive can be obtained by attaching a film adhesive to the back of a semiconductor wafer and singulating the semiconductor wafer by dicing. The obtained semiconductor chip with a film adhesive can be attached to a supporting member via the film adhesive and bonded by thermal compression.

[Prior art literature]

[Patent document 1] Japanese Patent Publication No. 2007-053240

However, as the size of semiconductor chips decreases, the force applied to each unit area during thermal compression bonding increases, and a phenomenon called bleed occurs in which the film adhesive protrudes from the semiconductor chip.

In addition, when the film adhesive is used as a film over wire (FOW) as a wire embedding film adhesive or a film over die (FOD) as a semiconductor chip embedding film adhesive, high fluidity is required during hot pressing to improve embedding properties. Therefore, there is a tendency for the frequency and amount of seepage to increase further. Depending on the situation, seepage may occur on the upper surface of the semiconductor chip. Furthermore, due to the flow of resin during the high-temperature pressurization process after hot pressing, the amount of seepage increases compared to hot pressing, which may cause electrical defects or poor wire bonding.

The present invention is made in view of this situation, and its main purpose is to provide an adhesive composition that has good embedding properties during hot pressing and can inhibit seepage during high temperature and pressure treatment.

One aspect of the present invention provides an adhesive composition comprising a thermosetting resin, a hardener and an elastomer, wherein the thermosetting resin comprises an epoxy resin having a lipid cyclic ring, and the elastomer comprises an elastomer having a carboxyl group. According to this adhesive composition, it has good embedding properties during heat pressing and can suppress seepage during high temperature and pressure treatment.

The hardener may include a phenolic resin. Additionally, the elastomer may include an acrylic resin.

The elastomer may further include an elastomer without a carboxyl group.

The thermosetting resin may further include an aromatic epoxy resin without an alicyclic ring. The aromatic epoxy resin without an alicyclic ring may be liquid at 25°C.

The adhesive composition may further contain an inorganic filler. In addition, the adhesive composition may further contain a hardening accelerator.

The adhesive composition can be used to press-bond the second semiconductor element and bury at least a portion of the first wire in a semiconductor device formed by connecting the first semiconductor element to a substrate by wire bonding via a first wire and pressing the second semiconductor element onto the first semiconductor element.

Furthermore, the present invention may be related to an application of a composition containing a thermosetting resin, a hardener and an elastomer, wherein the thermosetting resin includes an epoxy resin having a resin epoxide, as an adhesive or for manufacturing an adhesive, wherein the composition is used to press-bond the second semiconductor element and bury at least a portion of the first wire in a semiconductor device in which a first semiconductor element is connected to a substrate by wire bonding via a first wire and a second semiconductor element is press-bonded on the first semiconductor element.

Another aspect of the present invention provides a film-like adhesive, which is formed by forming the adhesive composition into a film.

Another aspect of the present invention provides a bonding sheet, which includes a substrate and the film-like bonding agent disposed on the substrate.

The substrate may be a dicing tape. Furthermore, in this specification, the bonding sheet whose substrate is a dicing tape is sometimes referred to as a "dicing and die-bonding integrated bonding sheet".

The adhesive sheet may further include a protective film, which is laminated on the surface of the film adhesive opposite to the substrate.

Furthermore, another aspect of the present invention provides a method for manufacturing a semiconductor device, comprising: a wire bonding step, electrically connecting a first semiconductor element on a substrate via a first wire; a lamination step, attaching the film adhesive to one side of a second semiconductor element; and a die bonding step, pressing the second semiconductor element attached with the film adhesive via the film adhesive, thereby burying at least a portion of the first wire in the film adhesive.

Furthermore, the semiconductor device may be a wire-embedded semiconductor device formed by connecting a first semiconductor chip to a semiconductor substrate by wire bonding via a first wire, and pressing a second semiconductor chip onto the first semiconductor chip via a bonding film, thereby burying at least a portion of the first wire in the bonding film; or a chip-embedded semiconductor device formed by burying the first wire and the first semiconductor chip in the bonding film.

According to the present invention, an adhesive composition can be provided that has good embedding properties during hot pressing and can suppress seepage during high-temperature pressurization. Therefore, the film-shaped adhesive formed by forming the adhesive composition into a film can be effectively used as a film over die (FOD) as a semiconductor chip embedding film-shaped adhesive or as a film over wire (FOW) as a wire embedding film-shaped adhesive. In addition, according to the present invention, a method for manufacturing an adhesive sheet and a semiconductor device using the film-shaped adhesive can be provided.

The following describes the implementation forms of the present invention with reference to the drawings as appropriate. However, the present invention is not limited to the following implementation forms.

In this manual, (meth)acrylic acid refers to acrylic acid or its corresponding methacrylic acid. The same applies to other similar expressions such as (meth)acryloyl.

[Adhesive composition]

The adhesive composition of this embodiment contains: (A) a thermosetting resin, (B) a hardener, and (C) an elastomer. The adhesive composition is thermosetting, and can be fully cured (stage C) after a semi-cured (stage B) state and a curing treatment.

<(A) Ingredients: Thermosetting resin>

From the viewpoint of adhesiveness, the thermosetting resin may contain an epoxy resin. The adhesive composition of this embodiment contains (A-1) an epoxy resin having an epoxide ring as the thermosetting resin.

The component (A-1) is a compound having an alicyclic ring and an epoxy group in the molecule. The epoxy group may be bonded to the alicyclic ring of the compound or a site other than the alicyclic ring via a single bond or a linking group (e.g., an alkylene group, an oxyalkylene group, etc.). In addition, the compound may also be a compound having an epoxy group formed together with two carbon atoms constituting the alicyclic ring (i.e., an alicyclic epoxy compound). By including the component (A-1) as a thermosetting resin, good embedding properties are achieved during heat pressing, and exudation during high temperature pressure treatment can be suppressed.

The epoxy equivalent of component (A-1) is not particularly limited and can be 90g/eq~600g/eq, 100g/eq~500g/eq, or 120g/eq~450g/eq. If the epoxy equivalent of component (A-1) is within this range, better reactivity and fluidity tend to be obtained.

The component (A-1) may be, for example, any of the epoxy resins represented by the following general formulas (1) to (4).

In formula (1), E represents an alicyclic ring, G represents a single bond or an alkylene group, ^R1 each independently represents a hydrogen atom or a monovalent hydrocarbon group, n1 represents an integer of 1 to 10, and m represents an integer of 1 to 3.

The number of carbon atoms of E may be 4 to 12, 5 to 11 or 6 to 10. E may be a monocyclic or polycyclic ring, preferably a polycyclic ring, and more preferably a dicyclopentadiene ring. The alkylene group in G may be an alkylene group having 1 to 5 carbon atoms such as methylene, ethylene, propylene, butylene, pentylene, etc. G is preferably a single bond. The monovalent hydrocarbon group in ^R1 may be, for example, an alkyl group such as methyl, ethyl, propyl, butyl, pentyl, etc.; an aryl group such as phenyl, naphthyl, etc.; a heteroaryl group such as pyridyl, etc. ^R1 is preferably a hydrogen atom.

The epoxy resin represented by the general formula (1) may be an epoxy resin represented by the following general formula (1a).

In formula (1a), n1 has the same meaning as described above.

Commercially available products of epoxy resins represented by general formula (1a) include, for example, HP-7200L, HP-7200H, HP-7200 (all manufactured by DIC Corporation); XD-1000 (manufactured by Nippon Kayaku Co., Ltd.), etc.

In formula (2), ^R2 represents a divalent hydrocarbon group.

The divalent alkyl group in R ² may be, for example, an alkylene group such as methylene, ethylene, propylene, butylene, pentylene, an arylene group such as phenylene, naphthylene, or a heteroarylene group such as pyridylene. R ² is preferably an alkylene group having 1 to 5 carbon atoms.

Commercially available products of epoxy resins represented by general formula (2) include, for example, Celloxide 2021P and Celloxide 2081 (both manufactured by Daicel Co., Ltd.).

In formula (3), R ³ , R ⁴ and R ⁵ each independently represent a divalent hydrocarbon group.

As the divalent hydrocarbon group for R ³ , R ⁴ and R ⁵ , there can be exemplified the same groups as exemplified for the divalent hydrocarbon group for R ² .

Commercially available products of epoxy resins represented by general formula (3) include, for example, Syna-Epoxy 28 (manufactured by SYNASIA)

In formula (4), R ⁶ represents a hydrogen atom or a monovalent hydrocarbon group, and n 2 represents an integer of 1 to 10.

As the monovalent hydrocarbon group for ^R6 , there can be exemplified the same groups as exemplified for the monovalent hydrocarbon group for ^R1 .

Commercially available products of epoxy resins represented by general formula (4) include, for example, EHPE3150 (manufactured by Daicell Co., Ltd.).

From the viewpoint of heat resistance, the component (A-1) is preferably an epoxy resin represented by the general formula (1), and more preferably an epoxy resin represented by the general formula (1a).

Based on the total amount of component (A), the content of component (A-1) may be 15% to 100% by mass. The content of component (A-1) may be 40% by mass or more, 50% by mass or more, or 60% by mass or more.

The content of component (A-1) can be 5% by mass or more, 10% by mass or more, or 20% by mass or more based on the total amount of the adhesive composition. If the content of component (A-1) is 5% by mass or more based on the total amount of the adhesive composition, it has better embedding properties during heat pressing and can fully suppress the tendency of seepage during high temperature pressure treatment.

In addition to the component (A-1), the component (A) may further include (A-2) an aromatic epoxy resin having no alicyclic ring. Here, the aromatic epoxy resin having no alicyclic ring is a compound having an aromatic ring and an epoxy group in the molecule and having no alicyclic ring. Examples of the component (A-2) include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, diphenylethylene type epoxy resin, tris-containing epoxy resin Epoxy resins containing an oxazine skeleton, epoxy resins containing a fluorene skeleton, trisphenolmethane type epoxy resins, biphenyl type epoxy resins, xylyl type epoxy resins, phenyl aralkyl type epoxy resins, biphenyl aralkyl type epoxy resins, naphthalene type epoxy resins, polyfunctional phenols, anthracene and other polycyclic aromatic diglycidyl ether compounds, etc. These can be used alone or in combination of two or more. Among these, component (A-2) can be liquid at 25°C.

The epoxy equivalent of component (A-2) is not particularly limited and can be 90g/eq~600g/eq, 100g/eq~500g/eq, or 120g/eq~450g/eq. If the epoxy equivalent of component (A-2) is within this range, better reactivity and fluidity tend to be obtained.

Based on the total amount of component (A), the content of component (A-2) may be 0% to 85% by mass. The content of component (A-2) may be less than 60% by mass, less than 50% by mass, or less than 40% by mass.

<(B) Component: Hardener>

There is no particular limitation on the component (B), and any component commonly used as a hardener for a thermosetting resin may be used. When the thermosetting resin includes an epoxy resin, the component (B) may include, for example, a phenolic resin, an ester compound, an aromatic amine, an aliphatic amine, an acid anhydride, and the like. These may be used alone or in combination of two or more. Among these, the component (B) may include a phenolic resin from the viewpoint of reactivity and stability over time.

The phenol resin can be used without particular limitation as long as it has a phenolic hydroxyl group in the molecule. Examples of the phenolic resin include: novolac-type phenolic resins obtained by condensing or co-condensing phenols such as phenol, cresol, resorcin, o-catechin, bisphenol A, bisphenol F, phenylphenol, and aminophenol and/or naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene with a compound having an aldehyde group such as formaldehyde under an acidic catalyst; phenol aralkyl resins, naphthol aralkyl resins, biphenyl aralkyl-type phenolic resins, and phenyl aralkyl-type phenolic resins synthesized from phenols such as allylated bisphenol A, allylated bisphenol F, allylated naphthalene diol, phenol novolac, phenol, and/or naphthols with dimethoxy-p-xylene or bis(methoxymethyl)biphenyl. These can be used alone or in combination of two or more. Among these, from the perspective of heat resistance, the phenolic resin is preferably one that has a water absorption rate of less than 2% by mass under the conditions of 85°C and 85%RH in a constant temperature and humidity bath for 48 hours, and a heating mass reduction rate at 350°C (heating rate: 5°C/min, environment: nitrogen) measured by a thermogravimetric analyzer (TGA) of less than 5% by mass.

Commercially available products of phenolic resins include: Phenolite KA series, TD series (manufactured by DIC Co., Ltd.); Mirex XLC series, XL series (manufactured by Mitsui Chemicals Co., Ltd.); HE series (manufactured by Air Water Co., Ltd.), etc.

The hydroxyl equivalent of the phenolic resin is not particularly limited and may be 80 g/eq to 400 g/eq, 90 g/eq to 350 g/eq, or 100 g/eq to 300 g/eq. If the hydroxyl equivalent of the phenolic resin is within this range, better reactivity and fluidity tend to be obtained.

From the viewpoint of curability, when the component (A) is an epoxy resin and the component (B) is a phenol resin, the ratio of the epoxy equivalent of the epoxy resin to the hydroxyl equivalent of the phenol resin (epoxy equivalent of the epoxy resin/hydroxyl equivalent of the phenol resin) may be 0.30/0.70 to 0.70/0.30, 0.35/0.65 to 0.65/0.35, 0.40/0.60 to 0.60/0.40, or 0.45/0.55 to 0.55/0.45. If the equivalent ratio is 0.30/0.70 or more, more sufficient curability tends to be obtained. If the equivalent ratio is 0.70/0.30 or less, the viscosity can be prevented from becoming too high, and more sufficient fluidity can be obtained.

Based on the total amount of the adhesive composition, the total content of the components (A) and (B) can be 30% to 70% by mass. The total content of the components (A) and (B) can be 33% or more, 36% or more, or 40% or more, and can be 65% or less, 60% or less, or 55% or less. If the total content of the components (A) and (B) is 30% or more based on the total amount of the adhesive composition, the adhesiveness tends to be improved. If the total content of the components (A) and (B) is 70% or less based on the total amount of the adhesive composition, the viscosity can be prevented from becoming too low, and the seepage during the high temperature and pressure treatment can be further suppressed.

<(C) Component: Elastomer>

The adhesive composition of this embodiment contains (C) an elastomer. As the elastomer, the adhesive composition of this embodiment contains (C-1) an elastomer having a carboxyl group. The component (C) is preferably a polymer constituting the elastomer whose glass transition temperature (Tg) is 50°C or less.

Component (C-1) is a compound (elastomer) having a carboxyl group in the molecule. By including component (C-1) as an elastomer, it has good embedding properties during heat pressing and can suppress the leakage during high temperature and pressure treatment.

As the component (C-1), for example, there can be mentioned acrylic resins, polyester resins, polyamide resins, polyimide resins, silicone resins, butadiene resins, acrylonitrile resins, and modified forms thereof.

From the viewpoint of solubility and fluidity in solvents, component (C-1) may include an acrylic resin having a carboxyl group. Here, the acrylic resin refers to a polymer containing a structural unit derived from a (meth)acrylate. The acrylic resin is preferably a polymer containing a structural unit derived from a (meth)acrylate having a cross-linking functional group other than a carboxyl group, such as an epoxy group, an alcoholic or phenolic hydroxyl group, as a structural unit. In addition, the acrylic resin may also be an acrylic rubber such as a copolymer of a (meth)acrylate and acrylonitrile.

The glass transition temperature (Tg) of the acrylic resin can be -50°C to 50°C or -30°C to 30°C. If the Tg of the acrylic resin is above -50°C, the flexibility of the adhesive composition tends to be prevented from becoming too high. This makes it easier to cut the film adhesive when the wafer is cut, and can prevent the generation of burrs. If the Tg of the acrylic resin is below 50°C, the flexibility of the adhesive composition tends to be suppressed from decreasing. This makes it easier to fully fill the gaps when the film adhesive is attached to the wafer. In addition, chipping during cutting caused by a decrease in the adhesion of the wafer can be prevented. Here, the glass transition temperature (Tg) is a value measured using a differential scanning calorimeter (DSC) (e.g., "Thermo Plus 2" manufactured by Rigaku Co., Ltd.).

The weight average molecular weight (Mw) of acrylic resin can be 100,000 to 3,000,000 or 500,000 to 2,000,000. If the Mw of acrylic resin is within this range, the film forming property, film strength, flexibility, viscosity, etc. can be properly controlled, and the reflow property is excellent, which can improve the embedding property. Here, Mw refers to the value measured by gel permeation chromatography (GPC) and converted using a calibration curve based on standard polystyrene.

From the perspective of hardenability, the acid value of component (C-1) may be 1mgKOH/g~60mgKOH/g, 2mgKOH/g~40mgKOH/g, or 3mgKOH/g~30mgKOH/g. If the acid value is within this range, there is a tendency to further suppress the seepage during high temperature and pressure treatment.

Commercially available products of component (C-1) (acrylic resin) include, for example, SG-70L, SG-708-6, WS-023 EK30, SG-280 EK23 (all manufactured by Nagase ChemteX Co., Ltd.), etc.

In addition to the component (C-1), the component (C) may further include an elastomer (C-2) having no carboxyl group. The component (C-2) is a compound (elastomer) having no carboxyl group in the molecule.

As the component (C-2), for example, there can be mentioned acrylic resins, polyester resins, polyamide resins, polyimide resins, silicone resins, butadiene resins, acrylonitrile resins, and modified forms thereof.

From the viewpoint of solubility and fluidity in solvents, component (C-2) may include an acrylic resin having no carboxyl group. Here, the acrylic resin refers to a polymer containing a structural unit derived from (meth)acrylate. The acrylic resin is preferably a polymer containing a structural unit derived from (meth)acrylate having a cross-linking functional group such as an epoxy group, alcoholic or phenolic hydroxyl group as a structural unit. In addition, the acrylic resin may also be an acrylic rubber such as a copolymer of (meth)acrylate and acrylonitrile.

The glass transition temperature (Tg) of the acrylic resin may be the same as the Tg of the acrylic resin of the component (C-1). The weight average molecular weight (Mw) of the acrylic resin may be the same as the Mw of the acrylic resin of the component (C-1).

Commercially available products of component (C-2) (acrylic resin) include, for example, SG-P3 and SG-80H (both manufactured by Nagase ChemteX Co., Ltd.).

The content of component (C) can be 20 to 200 parts by mass or 30 to 100 parts by mass relative to 100 parts by mass of the total amount of components (A) and (B). If the content of component (C) is 20 parts by mass or more relative to 100 parts by mass of components (A) and (B), the operability of the film adhesive (such as bendability, etc.) tends to be better. If the content of component (C) is 200 parts by mass or less relative to 100 parts by mass of components (A) and (B), the softness of the adhesive composition tends to be further prevented from becoming too high. Thereby, the film adhesive is easily cut during wafer dicing, and the generation of burrs is more likely to be prevented.

The mass ratio of the content of component (C-1) to the content of component (C) (the total content of component (C-1) and component (C-2)) (content of component (C-1)/content of component (C)) may be 0.05~1, 0.10~1, 0.20~1, 0.40~1, or 0.60~1.

<(D) Ingredient: Inorganic filler>

The adhesive composition of this embodiment may further contain (D) an inorganic filler. Examples of the inorganic filler include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whiskers, boron nitride, crystalline silicon dioxide, amorphous silicon dioxide, and the like. These may be used alone or in combination of two or more. From the viewpoint of further improving the thermal conductivity of the obtained film-like adhesive, the inorganic filler may include aluminum oxide, aluminum nitride, boron nitride, crystalline silicon dioxide, or amorphous silicon dioxide. In addition, from the viewpoint of adjusting the melt viscosity of the adhesive composition and imparting thixotropic properties to the adhesive composition, the inorganic filler may include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, crystalline silicon dioxide, or amorphous silicon dioxide.

From the perspective of further improving adhesion, the average particle size of component (D) may be 0.005μm~0.5μm or 0.05μm~0.3μm. Here, the average particle size refers to the value calculated by converting the Brunauer-Emmett-Teller (BET) specific surface area.

From the perspective of compatibility of the surface with solvents, other components, etc., and bonding strength, component (D) can be surface treated with a surface treatment agent. Examples of surface treatment agents include silane coupling agents, etc. Examples of functional groups of silane coupling agents include: vinyl, (meth)acryl, epoxy, butyl, amino, diamine, alkoxy, ethoxy, etc.

The content of component (D) may be 10 to 90 parts by mass or 10 to 50 parts by mass relative to 100 parts by mass of the total amount of components (A), (B) and (C). If the content of component (D) is 10 parts by mass or more relative to 100 parts by mass of the total amount of components (A), (B) and (C), the cutting property of the adhesive layer before curing tends to be improved, and the bonding force of the adhesive layer after curing tends to be improved. If the content of component (D) is 90 parts by mass or less relative to 100 parts by mass of the total amount of components (A), (B) and (C), the decrease in fluidity can be suppressed, and the elastic modulus of the film adhesive after curing can be prevented from becoming too high.

<(E) Ingredient: Hardening accelerator>

The adhesive composition of this embodiment may contain (E) a hardening accelerator. The hardening accelerator is not particularly limited, and any commonly used one may be used. Examples of the (E) component include: imidazoles and their derivatives, organic phosphorus compounds, diamines, tertiary amines, quaternary ammonium salts, etc. These may be used alone or in combination of two or more. Among these, from the perspective of reactivity, the (E) component may be imidazoles and their derivatives.

Examples of imidazoles include 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl-2-methylimidazole. These can be used alone or in combination of two or more.

The content of component (E) can be 0.04 to 3 parts by mass or 0.04 to 0.2 parts by mass relative to 100 parts by mass of the total amount of component (A), component (B) and component (C). If the content of component (E) is within this range, it tends to have both hardening and reliability.

<Other ingredients>

The adhesive composition of this embodiment may further contain antioxidants, silane coupling agents, rheology control agents, etc. as other components. The content of these components may be 0.02 to 3 parts by mass relative to 100 parts by mass of the total amount of component (A), component (B), and component (C).

The adhesive composition of this embodiment can be used as an adhesive varnish diluted with a solvent. The solvent is not particularly limited as long as it can dissolve components other than the component (D). Examples of the solvent include aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, and p-isopropyltoluene; aliphatic hydrocarbons such as hexane and heptane; cyclic alkanes such as methylcyclohexane; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, and γ-butyrolactone; carbonates such as ethyl carbonate and propyl carbonate; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone, etc. These may be used alone or in combination of two or more. Among these, from the viewpoint of solubility and boiling point, the solvent may be toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone.

Based on the total mass of the adhesive varnish, the solid content concentration in the adhesive varnish can be 10% to 80% by mass.

The adhesive varnish can be prepared by mixing and kneading the components (A), (B), (C) and solvent, and optionally the components (D), (E) and other components. The mixing and kneading can be performed by appropriately combining a common agitator, a mortar, a three-rod roll mill, a ball mill, a bead mill and other dispersers. When the component (D) is contained, the mixing time can be shortened by premixing the component (D) with the low molecular weight component and then mixing the high molecular weight component. In addition, after the adhesive varnish is prepared, the bubbles in the varnish can be removed by vacuum degassing or the like.

[Film adhesive]

FIG1 is a schematic cross-sectional view of a film adhesive of an embodiment. The film adhesive 10 is formed by forming the above-mentioned adhesive composition into a film. The film adhesive 10 may be in a semi-cured (B stage) state. Such a film adhesive 10 may be formed by applying the adhesive composition to a support film. When an adhesive varnish is used, the adhesive varnish may be applied to the support film and heated and dried to remove the solvent, thereby forming the film adhesive 10.

There is no particular limitation on the supporting membrane, for example, membranes of polytetrafluoroethylene, polyethylene, polypropylene, polymethylpentene, polyethylene terephthalate, polyimide, etc. The thickness of the supporting membrane can be, for example, 60μm~200μm or 70μm~170μm.

As a method for applying the adhesive varnish to the support film, a known method can be used, for example, scraping, roller, spray, gravure, rod, curtain, etc. The conditions for heat drying are not particularly limited as long as the solvent used is fully volatilized, for example, 0.1 minutes to 90 minutes at 50°C to 200°C.

The thickness of the film adhesive can be adjusted appropriately according to the application. From the perspective of fully embedding the bumps and concavities of semiconductor chips, wires, wiring circuits on substrates, etc., the thickness of the film adhesive can be 20μm~200μm, 30μm~200μm, or 40μm~150μm.

[Continuation]

FIG2 is a schematic cross-sectional view of a bonding sheet in an embodiment. The bonding sheet 100 includes a substrate 20 and the above-mentioned film-shaped bonding agent 10 disposed on the substrate.

The substrate 20 is not particularly limited and may be a substrate film. The substrate film may be the same as the supporting film.

The substrate 20 may be a dicing tape. This type of adhesive sheet may be used as a dicing and bonding integrated adhesive sheet. In this case, since the lamination step of the semiconductor wafer is performed once, the operation can be performed efficiently.

Examples of dicing tapes include polytetrafluoroethylene film, polyethylene terephthalate film, polyethylene film, polypropylene film, polymethylpentene film, polyimide film and other plastic films. In addition, the dicing tape may be subjected to surface treatments such as primer coating, UV treatment, corona discharge treatment, grinding treatment, and etching treatment as needed. The dicing tape is preferably adhesive. Such a dicing tape may be one that imparts adhesiveness to the plastic film, or one that has an adhesive layer on one side of the plastic film.

The adhesive sheet 100 can be formed by applying the adhesive composition to the substrate film in the same manner as the method for forming the film-like adhesive described above. The method for applying the adhesive composition to the substrate 20 can be the same as the method for applying the adhesive composition described above to the supporting film.

The adhesive sheet 100 can be formed using a pre-made film adhesive. In this case, the adhesive sheet 100 can be formed by laminating using a roller press, a vacuum laminating press, etc. under specified conditions (e.g., room temperature (20°C) or heated). The adhesive sheet 100 can be manufactured continuously, and in terms of efficiency, it is preferably formed using a roller press in a heated state.

From the perspective of embedding the semiconductor chip, wire, wiring circuit of the substrate, etc., the thickness of the film adhesive 10 can be 20μm~200μm, 30μm~200μm, or 40μm~150μm. If the thickness of the film adhesive 10 is 20μm or more, there is a tendency to obtain a more sufficient bonding force, and if the thickness of the film adhesive 10 is 200μm or less, it is economical and can respond to the requirements of miniaturization of semiconductor devices.

FIG3 is a schematic cross-sectional view of another embodiment of the bonding sheet. The bonding sheet 110 further includes a protective film 30 laminated on the surface of the film-like adhesive 10 opposite to the substrate 20. The protective film 30 may be the same as the supporting film described above. The thickness of the protective film may be, for example, 15 μm to 200 μm or 70 μm to 170 μm.

[Semiconductor devices]

FIG4 is a schematic cross-sectional view of a semiconductor device according to an embodiment. The semiconductor device 200 is formed by connecting the first semiconductor element Wa in the first stage to the substrate 14 by wire bonding via the first wire 88, and by pressing the second semiconductor element Waa onto the first semiconductor element Wa via the film adhesive 10, thereby burying at least a portion of the first wire 88 in the film adhesive 10. The semiconductor device may be a wire-embedded semiconductor device in which at least a portion of the first wire 88 is embedded, or may be a semiconductor device in which the first wire 88 and the first semiconductor element Wa are embedded. In addition, in the semiconductor device 200, the substrate 14 is electrically connected to the second semiconductor element Waa via the second wire 98, and the second semiconductor element Waa is sealed by the sealing material 42.

The thickness of the first semiconductor element Wa can be 10μm~170μm, and the thickness of the second semiconductor element Waa can be 20μm~400μm. The first semiconductor element Wa embedded in the film adhesive 10 is a controller chip for driving the semiconductor device 200.

The substrate 14 includes an organic substrate 90 with circuit patterns 84 and 94 formed at two locations on the surface. The first semiconductor element Wa is pressed onto the circuit pattern 94 via an adhesive 41. The second semiconductor element Waa is pressed onto the substrate 14 via a film adhesive 10 in a manner that covers the circuit pattern 94 to which the first semiconductor element Wa is not pressed, the first semiconductor element Wa, and a portion of the circuit pattern 84. The film adhesive 10 is embedded in the uneven step caused by the circuit patterns 84 and 94 on the substrate 14. In addition, the second semiconductor element Waa, the circuit pattern 84, and the second wire 98 are sealed using a resin sealant 42.

[Method for manufacturing semiconductor device]

The manufacturing method of the semiconductor device of this embodiment includes: a first wire bonding step of electrically connecting a first semiconductor element on a substrate via a first wire; a lamination step of attaching the above-mentioned film adhesive to one side of a second semiconductor element; and a die bonding step of pressing the second semiconductor element attached with the film adhesive via the film adhesive to bury at least a portion of the first wire in the film adhesive.

FIG. 5 to FIG. 9 are schematic cross-sectional views showing a series of steps of a method for manufacturing a semiconductor device of an embodiment. The semiconductor device 200 of this embodiment is a semiconductor device in which a first wire 88 and a first semiconductor element Wa are embedded, and can be manufactured by the following procedure. First, as shown in FIG. 5 , a first semiconductor element Wa having a bonding agent 41 is pressed onto a circuit pattern 94 on a substrate 14, and the circuit pattern 84 on the substrate 14 is electrically bonded to the first semiconductor element Wa via the first wire 88 (first wire bonding step).

Next, a laminating adhesive sheet 100 is laminated on one side of a semiconductor wafer (e.g., 100 μm thick and 8 inches in size), and the substrate 20 is peeled off, thereby attaching a film adhesive 10 (e.g., 110 μm thick) to one side of the semiconductor wafer. Furthermore, after attaching a dicing tape to the film adhesive 10, it is cut into a specified size (e.g., 7.5 mm square), thereby obtaining a second semiconductor element Waa (laminating step) attached with the film adhesive 10 as shown in FIG. 6 .

The temperature condition of the lamination step can be 50℃~100℃ or 60℃~80℃. If the temperature of the lamination step is above 50℃, good adhesion with the semiconductor wafer can be obtained. If the temperature of the lamination step is below 100℃, the film adhesive 10 can be suppressed from excessively flowing during the lamination step, thereby preventing changes in thickness, etc.

Examples of cutting methods include: cutting with a blade having a rotating blade, and cutting a film adhesive or both a wafer and a film adhesive by laser.

Furthermore, the second semiconductor element Waa with the film adhesive 10 is pressed onto the substrate 14 to which the first semiconductor element Wa is connected via the first wire 88. Specifically, as shown in FIG7 , the second semiconductor element Waa with the film adhesive 10 is mounted so as to cover the first wire 88 and the first semiconductor element Wa with the film adhesive 10, and then, as shown in FIG8 , the second semiconductor element Waa is fixed to the substrate 14 by pressing the second semiconductor element Waa onto the substrate 14 (die bonding step). The die bonding step is preferably performed by pressing the film adhesive 10 at 80° C. to 180° C. and 0.01 MPa to 0.50 MPa for 0.5 seconds to 3.0 seconds. After the die bonding step, as a high temperature and pressure treatment, the film adhesive 10 is pressurized and heated at 60°C to 175°C and 0.3MPa to 0.7MPa for more than 5 minutes.

Next, as shown in FIG. 9 , after the substrate 14 and the second semiconductor element Waa are electrically connected via the second wire 98 (second wire bonding step), the circuit pattern 84, the second wire 98 and the second semiconductor element Waa are sealed with a sealing material 42. By going through such steps, the semiconductor device 200 can be manufactured.

As another embodiment, the semiconductor device may be a wire-embedded semiconductor device in which at least a portion of the first wire 88 is embedded.

[Implementation example]

The following examples are given to explain the present invention in more detail. However, the present invention is not limited to these examples.

(Examples 1 to 8 and Comparative Examples 1-1 to 1-3, Comparative Examples 2 to 4)

<Production of the follow-up film>

The components shown below were mixed in the proportions (mass parts) shown in Tables 1, 2 and 3, and cyclohexanone was used as a solvent to prepare a varnish of an adhesive composition having a solid content of 40 mass%. Next, the obtained varnish was filtered using a 100-mesh filter and vacuum defoamed. The vacuum defoamed varnish was applied to a 38 μm thick polyethylene terephthalate (PET) film that had been subjected to a demolding treatment as a substrate film. The applied varnish was heat-dried in two stages at 90°C for 5 minutes and then at 140°C for 5 minutes. In this way, a bonding sheet having a film-like adhesive with a thickness of 110 μm in a semi-cured (B stage) state on the substrate film is obtained.

Furthermore, the components in Table 1, Table 2 and Table 3 are as follows.

(A) Thermosetting resin

(A-1) Epoxy resin having a lipid ring

A-1-1: Epoxy resin represented by general formula (1a) (epoxy resin with dicyclopentadiene structure), manufactured by DIC Corporation, trade name: HP-7200L, epoxy equivalent: 250g/eq~280g/eq

A-1-2: Epoxy resin represented by general formula (1a) (epoxy resin having a dicyclopentadiene structure), manufactured by Nippon Kayaku Co., Ltd., trade name: XD-1000, epoxy equivalent: 254 g/eq

A-1-3: Epoxy resin represented by general formula (2) (liquid at 25°C), manufactured by Cellulose Co., Ltd., trade name: Celloxide 2021P, epoxy equivalent: 128g/eq~145g/eq

A-1-4: Epoxy resin represented by general formula (4), manufactured by Daicellul Co., Ltd., trade name: EHPE3150, epoxy equivalent: 170g/eq~190g/eq

(A-2) Aromatic epoxy resin without alicyclic ring

A-2-1: Multifunctional aromatic epoxy resin, manufactured by Printec Co., Ltd., trade name: VG3101L, epoxy equivalent: 210g/eq

A-2-2: Cresol novolac type epoxy resin, manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., trade name: YDCN-700-10, epoxy equivalent: 209g/eq

A-2-3: Bisphenol F type epoxy resin (liquid at 25°C), manufactured by DIC Corporation, trade name: EXA-830CRP, epoxy equivalent: 159g/eq

(B) Hardener

B-1: Bisphenol A novolac type phenolic resin, manufactured by DIC Corporation, trade name: LF-4871, hydroxyl equivalent: 118g/eq

B-2: Phenyl aralkyl phenol resin, manufactured by Mitsui Chemicals Co., Ltd., trade name: XLC-LL, hydroxyl equivalent: 175g/eq

B-3: Phenyl aralkyl phenol resin, manufactured by Air Water Co., Ltd., trade name: HE100C-30, hydroxyl equivalent: 170g/eq

(C) Elastic body

(C-1) Elastomer with carboxyl group

C-1-1: Carboxyl-containing acrylic resin (acrylic rubber), manufactured by Nagase Chemicals Co., Ltd., trade name: SG-70L, weight average molecular weight: 900,000, acid value: 5mgKOH/g, Tg: -13℃

C-1-2: Carboxyl-containing acrylic resin (acrylic rubber), manufactured by Nagase Chemicals Co., Ltd., trade name: SG-708-6, weight average molecular weight: 700,000, acid value: 9 mgKOH/g, Tg: 4°C

C-1-3: Carboxyl-containing acrylic resin (acrylic rubber), manufactured by Nagase Chemicals Co., Ltd., trade name: WS-023 EK30, weight average molecular weight: 500,000, acid value: 20mgKOH/g, Tg: -10℃

(C-2) Elastomer without carboxyl group

C-2-1: Carboxyl-free epoxy-containing acrylic resin (acrylic rubber), manufactured by Nagase Chemicals Co., Ltd., trade name: SG-P3 solvent variant, weight average molecular weight: 800,000, Tg: 12°C

C-2-2: Epoxy-containing acrylic resin (acrylic rubber) without carboxyl group, manufactured by Nagase Chemical Co., Ltd., trade name: SG-80H, weight average molecular weight: 350,000, Tg: 11℃

(D) Inorganic fillers

D-1: Silica filler dispersion, fused silica, manufactured by Admatechs Co., Ltd., trade name: SC2050-HLG, average particle size: 0.50μm

(E) Hardening accelerator

E-1: 1-cyanoethyl-2-phenylimidazole, manufactured by Shikoku Chemical Industries, Ltd., trade name: Curezol 2PZ-CN

<Evaluation of various physical properties>

The obtained adhesive sheets were evaluated for embedding properties and seepage.

[Embeddedness Evaluation]

The following evaluation samples were prepared to evaluate the embedding properties of the bonding sheet. For the film-like adhesive (thickness 110μm) obtained above, the base film was peeled off and attached to the dicing tape to obtain a dicing-bonding integrated bonding sheet. Next, a 100μm thick semiconductor wafer (8 inches) was heated to 70°C and attached to the adhesive side. Thereafter, the semiconductor wafer was cut into 7.5mm squares to obtain a semiconductor chip A. Next, a dicing-bonding integrated bonding sheet (manufactured by Hitachi Chemical Co., Ltd., trade name: HR9004-10) (thickness 10μm) was prepared, heated to 70°C and attached to a 50μm thick semiconductor wafer (8 inches). Afterwards, the semiconductor wafer was cut into 4.5 mm squares to obtain a semiconductor chip B with a die-bonding film. Next, a 260 μm thick evaluation substrate coated with a solder resist (manufactured by Taiyo Nippon Sanso Co., Ltd., trade name: AUS308) was prepared, and the die-bonding film of the semiconductor chip B with a die-bonding film was brought into contact with the solder resist of the evaluation substrate, and pressure-bonded at 120°C, 0.20 MPa, and 2 seconds. Afterwards, the film adhesive of the semiconductor chip A was brought into contact with the semiconductor wafer of the semiconductor chip B, and pressure-bonded at 120°C, 0.20 MPa, and 1.5 seconds to obtain an evaluation sample. At this time, the position is aligned in such a way that the previously pressed semiconductor chip B is located in the center of the semiconductor chip A. For the evaluation samples obtained in the above manner, an ultrasonic digital image diagnostic device (manufactured by Insight Co., Ltd., probe: 75MHz) is used to observe the presence of voids. When voids are observed, the ratio of the area of voids per unit area is calculated, and these analysis results are used as embedding properties for evaluation. The evaluation criteria are as follows. The results are shown in Tables 1, 2, and 3.

A: No gaps were observed.

B: Although voids were observed, their proportion was less than 5% by area.

C: Voids are observed and their proportion is 5% by area or more.

[Evaluation of exudate]

The samples evaluated as "A" or "B" in the embedding evaluation were evaluated for the amount of seepage. The samples were prepared in the same manner as the evaluation samples prepared in the embedding evaluation, and were subjected to high temperature pressurization treatment (pressurization curing) at 140°C, 0.7MPa, and 30 minutes in a pressurized oven to prepare samples for the seepage evaluation. The amount of seepage of the film adhesive was measured from the center of the four sides of the evaluation sample using a microscope, and the maximum value was set as the amount of seepage. The results are shown in Tables 1, 2, and 3.

Table 3

As shown in Table 1, the adhesive composition of Example 1, which includes an epoxy resin having an alicyclic ring and an elastomer including an elastomer having a carboxyl group, can maintain good embedding properties and suppress bleeding during high temperature and pressure treatment, compared with the adhesive compositions of Comparative Examples 1-1 to Comparative Examples 1-3 that do not include these. In addition, as can be seen from Examples 2 and 3 in Table 2 and Examples 4 to 8 in Table 3, the same tendency is also observed when other epoxy resins having an alicyclic ring or other elastomers having a carboxyl group are used. Based on these results, it was confirmed that the adhesive composition of the present invention has good embedding properties during hot pressing and can inhibit seepage during high temperature and pressure treatment.

[Industrial availability]

As shown in the above results, the adhesive composition of the present invention has good embedding properties during hot pressing and can suppress leakage during high-temperature pressure treatment. Therefore, the film-shaped adhesive formed by forming the adhesive composition into a film can be effectively used as a film over die (FOD) as a chip embedding type film adhesive or a film over wire (FOW) as a wire embedding type film adhesive.

10: Film adhesive

14: Substrate

20: Base material

30: Protective film

41: Follow-up agent

42: Sealing material

84, 94: Circuit diagram

88: First Lead

90: Organic substrate

98: Second wire

100, 110: Next film

200:Semiconductor devices

Wa: First semiconductor element

Waa: Second semiconductor element

Figure 1 is a schematic cross-sectional view showing a film-like adhesive in one embodiment.

Figure 2 is a schematic cross-sectional view showing a bonding sheet in an implementation form.

Figure 3 is a schematic cross-sectional view of another embodiment of the connecting sheet.

FIG4 is a schematic cross-sectional view showing a semiconductor device of an embodiment.

FIG5 is a schematic cross-sectional view showing a series of steps of a method for manufacturing a semiconductor device in an embodiment.

FIG6 is a schematic cross-sectional view showing a series of steps of a method for manufacturing a semiconductor device in an embodiment.

FIG7 is a schematic cross-sectional view showing a series of steps of a method for manufacturing a semiconductor device in an embodiment.

FIG8 is a schematic cross-sectional view showing a series of steps of a method for manufacturing a semiconductor device in an embodiment.

FIG9 is a schematic cross-sectional view showing a series of steps of a method for manufacturing a semiconductor device in an embodiment.

Claims (11)

A bonding agent composition comprises: a thermosetting resin, a hardener, and an elastomer, wherein the hardener comprises a phenol resin, the thermosetting resin comprises an epoxy resin having an alicyclic epoxy group, the elastomer comprises an acrylic resin having a carboxyl group, the epoxy resin having an alicyclic epoxy group is an epoxy resin represented by the following general formula (2), an epoxy resin represented by the following general formula (3), and an epoxy resin represented by the following general formula (4).

In formula (2), ^R2 represents a divalent hydrocarbon group,

In formula (3), R ³ , R ⁴ and R ⁵ each independently represent a divalent hydrocarbon group,

In formula (4), R ⁶ represents a hydrogen atom or a monovalent hydrocarbon group, and n 2 represents an integer of 1 to 10. The adhesive composition as described in claim 1, wherein the elastomer further comprises an elastomer without a carboxyl group. The adhesive composition as described in claim 1 or claim 2, wherein the thermosetting resin further comprises an aromatic epoxy resin without an alicyclic ring. The adhesive composition as described in claim 3, wherein the aromatic epoxy resin without alicyclic rings is liquid at 25°C. The adhesive composition as described in claim 1 or claim 2 further contains an inorganic filler. The adhesive composition as described in claim 1 or claim 2 further contains a hardening accelerator. A film-like adhesive, which is formed by forming the adhesive composition described in any one of claim 1 to claim 6 into a film. A bonding sheet, comprising: a substrate; and a film-like bonding agent as described in claim 7 disposed on the substrate. A splice sheet as described in claim 8, wherein the substrate is a cutting tape. The adhesive sheet as described in claim 8 or claim 9 further includes a protective film, wherein the protective film is laminated on the surface of the film adhesive opposite to the substrate. A method for manufacturing a semiconductor device, comprising: a wire bonding step, electrically connecting a first semiconductor element on a substrate via a first wire; a lamination step, attaching a film adhesive as described in claim 7 to one side of a second semiconductor element; and a die bonding step, pressing the second semiconductor element attached with the film adhesive via the film adhesive, thereby burying at least a portion of the first wire in the film adhesive.

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